I know that Cahokia, a city near modern St Louis was bigger than London when the pilgrims came over, but became abandoned not long after vikings came to the new world.
I'm a bit confused; the abortive Norse settlement of the New World was some 450 years before the first Spaniard arrived in the hemisphere, and some 550 before the first English colony was established. Or am I totally misreading your question?
hi! fyi, you'll find lots of info in this in the FAQ - check out the first half dozen posts in this section